Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TB/C3 hybridoma cells were transected with either pEF-MClneopA or pEF bcl2-MClneopA vectors to produce a control cell line (TB/C3 pEF) and a cell line that overexpresses the "antiapoptotic" human bcl-2 protein (TB/C3 bcl2). Flow cytometry analysis of intracellular bcl-2 protein levels enabled near on-line monitoring of the stability of bcl-2 expression in the absence of drug selection. It was possible to maintain spontaneous selection of cells with the overexpression of bcl-2 protein during semicontinuous cultures at very low dilution rates, where cells were subjected to the selective conditions of nutrient limitation and high toxic metabolite concentrations. Interestingly, cells that overexpressed bcl-2 were adapted to suspension culture conditions significantly faster than control cells. Dual fluorescence staining with acridine orange and propidium iodide allowed for discrimination between viable, apoptotic, secondary necrotic, and necrotic cells, respectively. Compared with the usual trypan blue method of establishing culture viability, dual staining demonstrated that under stressful conditions a significant proportion of cells that excluded trypan blue were also undergoing cell death through apoptosis. In batch cultures the overexpression of bcl-2 more than doubled the membrane intact (MI) cell productive period (the integral of Ml cell density with respect to culture time) and increased the monoclonal antibody (mAb) production by approximately 40% when compared with the control cell line. The overexpression of bcl-2 protein also significantly extended the cell integrity and viability by the suppression of apoptosis in conditions of hypoxia, hyperoxia, glutamine deprivation, glucose deprivation, and serum limitation. The suppression of apoptosis in anaerobic conditions suggests that bcl-2 exerts its antiapoptotic activity by a mechanism that does not involve an oxidative reactive pathway. In conditions of excess thymidine, which suppressed cell proliferation, Ml cell density and specific mAb productivity were further enhanced by the overexpression of bcl-2, which suggests the possibility of accomplishing a controlled proliferation in immortalized cell lines without invoking cell death. Cell size and intracellular mAb were increased for TB/C3 bcl2 cells compared with TB/C3 pEF control cells when analyzed by flow cytometry.
 ...
PMID:Prevention of hybridoma cell death by bcl-2 during suboptimal culture conditions. 1863 67

Exposure to various toxicants is known to cause apoptosis in various cell types. The spermatogenic cells are particularly sensitive to various deleterious conditions including toxicant exposure. The affected cells might undergo apoptosis; however, the mechanisms may be different for different kinds of insults to the cells. In the present study, we looked into the mechanisms involved in apoptosis after exposure of testicular cells from mice to two different chemicals, diethyl maleate (DEM) and tert-butyl hydroperoxide (TBHP). For the study, cells were maintained for 4 h under various treatments: control (media only), 0.25 mM DEM, 0.5 mM DEM, 0.25 mM TBHP, and 0.5 mM TBHP. The treated cells were then harvested for various estimations, viz. viability, reduced and oxidized glutathione, redox ratio, free radical generation, and ethidium bromide/acridine orange co-staining. mRNA was extracted for RT-PCR analysis of Caspase 3, Caspase 8, Caspase 9, p53, p21, Bax, and Bcl-2. It was observed that both the treatments resulted in decreased levels of reduced glutathione and a concomitant increase in the oxidized form and ROS levels in a dose-dependent manner. The apoptotic cell death was evident from ethidium bromide/acridine orange staining. The mRNA expression pattern of various Caspases showed progressive increase in Caspase 3 and Caspase 9 mRNA in both the treatments in a dose-dependent manner, whereas there was no change in Caspase 8 mRNA expression. p53, p21, and Bax also showed increased expression, whereas Bcl-2 expression remained unchanged in DEM treatments and increased significantly in both TBHP treatments. Hence, the present study indicates the involvement and activation of various apoptotic factors, particularly Caspase 3 and 9 along with p53, in response to exposure of testicular cells to DEM and TBHP.
 ...
PMID:Regulation of apoptosis by Caspases under oxidative stress conditions in mice testicular cells: in vitro molecular mechanism. 1897 86

The Bcl-2 family of proteins is critical to the life and death of malignant B-lymphocytes. Interfering with their activity using small-molecule inhibitors (SMI) is being explored as a new therapeutic strategy for treating B-cell tumors. We evaluated the efficacy of TW-37, a non-peptidic SMI of Bcl-2 against a range spectrum of human B-cell lines, fresh patient samples and animal xenograft models. Multiple cytochemical and molecular approaches such as acridine orange/ethidium bromide assay for apoptosis, co-immunoprecipitation of complexes and western blot analysis, caspase luminescent activity assay and apoptotic DNA fragmentation assay were used to demonstrate the effect of TW-37 on different B-cell lines, patient derived samples, as well as in animal xenograft models. Nanomolar concentrations of TW-37 were able to induce apoptosis in both fresh samples and established cell lines with IC50 in most cases of 165-320 nM. Apoptosis was independent of proliferative status or pathological classification of B-cell tumor. TW-37 was able to block Bim-Bcl-XL and Bim-Mcl-1 heterodimerization and induced apoptosis via activation of caspases -9, -3, PARP and DNA fragmentation. TW-37 administered to tumor-bearing SCID mice led to significant tumor growth inhibition (T/C), tumor growth delay (T-C) and Log10kill, when used at its maximum tolerated dose (40 mg/kg x 3 days) via tail vein. TW-37 failed to induce changes in the Bcl-2 proteins levels suggesting that assessment of baseline Bcl-2 family proteins can be used to predict response to the drug. These findings indicate activity of TW-37 across the spectrum of human B-cell tumors and support the concept of targeting the Bcl-2 system as a therapeutic strategy regardless of the stage of B-cell differentiation.
 ...
PMID:SMI of Bcl-2 TW-37 is active across a spectrum of B-cell tumors irrespective of their proliferative and differentiation status. 1922 Aug 84

Hexabromocyclododecane (HBCD) is widely used as a brominated flame retardant, and has been detected in the aquatic environment, wild animals, and humans. However, details of the environmental health risk of HBCD are not well known. In this study, zebrafish embryos were used to assess the developmental toxicity of the chemical. Four-hour post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of HBCD (0, 0.05, 0.1, 0.5, and 1.0 mg L(-1)) until 96 h. Exposure to 0.1, 0.5, and 1.0 mg L(-1) HBCD significantly increased the malformation rate and reduced survival in the 0.5 and 1.0 mg L(-1) HBCD exposure groups. Acridine orange (AO) staining showed that HBCD exposure resulted in cell apoptosis. Reactive oxygen species (ROS) was significantly induced at exposures of 0.1, 0.5, and 1.0 mg L(-1) HBCD. To test the apoptotic pathway, several genes related to cell apoptosis, such as p53, Puma, Apaf-1, caspase-9, and caspase-3, were examined using real-time PCR. The expression patterns of these genes were up-regulated to some extent. Two anti-apoptotic genes, Mdm2 (antagonist of p53) and Bcl-2 (inhibitor of Bax), were down-regulated, and the activity of capspase-9 and caspase-3 was significantly increased. The overall results demonstrate that waterborne HBCD is able to produce oxidative stress and induce apoptosis through the involvement of caspases in zebrafish embryos. The results also indicate that zebrafish embryos can serve as a reliable model for the developmental toxicity of HBCD.
 ...
PMID:Hexabromocyclododecane-induced developmental toxicity and apoptosis in zebrafish embryos. 1935 5

This study examined the mechanism by which the gastric cancer cells lead to early peritoneal metastasis. HMrSV5 cells, a human peritoneal mesothelial cell line, were co-incubated with the supernatants of gastric cancer cells. Morphological changes of HMrSV5 cells were observed. The cell damage was quantitatively determined by MTT assay. The apoptosis of HMrSV5 cells was observed under transmission electron microscope. Acridine orange/ethidium bromide-stained condensed nuclei was detected by fluorescent microscopy and flow cytometry. The expressions of Bcl-2 and Bax was immunochemically evaluated. The results showed that conspicuous morphological changes of apoptosis were observed in HMrSV5 cells 24 h after treatment with the supernatants of gastric cancer cells. The supernatants could induce apoptosis of HMrSV5 cells in a time-dependent manner. The supernatants could up-regulate the expression of Bax and suppress that of Bcl-2 in HMrSV5 cells. These findings demonstrated that gastric cancer cells can induce the apoptosis of HPMCs through supernatants in the early peritoneal metastasis. The abnormal expressions of Bcl-2 and Bax may contribute to the apoptosis. Anti-apoptosis drugs promise to be adjuvant chemotherapeutic agents in the treatment of peritoneal metastasis of gastric cancer.
 ...
PMID:Destruction of gastric cancer cells to mesothelial cells by apoptosis in the early peritoneal metastasis. 1939 97

Quercetin, a widely distributed bioflavonoid, has been shown to induce growth inhibition in a variety of human cancer cells. However, the regulation of survivin and Bcl-2 on the quercetin-induced cell-growth inhibition and apoptosis in cancer cells remains unclear. In the present study, we report that quercetin can inhibit proliferation and induce apoptosis in HepG2 cells in dose- and time-dependent manner. Hoechst 33258 and acridine orange/ethidium bromide (AO/EB) staining showed that HepG2 cells underwent the typical morphologic changes of apoptosis characterized by nuclear shrinkage, chromatin condensation, or fragmentation after exposure to quercetin. Cell-cycle analysis reveals a significant increase of the proportion of cells in G(0)/G(1) phase. We also demonstrate that the levels of survivin and Bcl-2 protein expression in HepG2 cells decreased concurrently, and the levels of p53 protein increased significantly after treatment with quercetin by immunocytochemistry analysis. Relative activity of caspase-3 and caspase-9 increased significantly. These data clearly indicate that quercetin-induced apoptosis is associated with caspase activation, and the levels of survivin and Bcl-2. Our results indicate that the expression of survivin may be associated with Bcl-2 expression, and the inhibition expression of survivin, in conjunction with Bcl-2, might cause more pronounced apoptotic effects. Together, concurrent down-regulated survivin and Bcl-2 play an important role in HepG2 cell apoptosis induced by quercetin.
 ...
PMID:Regulation of survivin and Bcl-2 in HepG2 cell apoptosis induced by quercetin. 1962 60

The release of cytochrome c from the mitochondria to the cytosol is a critical step for downstream caspase-mediated apoptotic signal transduction in ischemia-reperfusion (I/R)-induced myocardial tissue injury. 10-N-nonyl acridine orange (NAO), a cardiolipin-specific dye, has been shown to inhibit Bid-mediated cytochrome c release from isolated mitochondria in vitro; however, the possible protective effects of NAO and the mechanisms underlying the protection from myocardial I/R-induced tissue injury in a rat model are unknown. Male Sprague-Dawley rats were subjected to a 30-min coronary arterial occlusion followed by reperfusion. All rats received either vehicle or NAO (100 microg/kg iv) 10 min before the occlusion. The infarct size in the heart at 24 h after reperfusion was significantly reduced in NAO-treated rats compared with vehicle-treated rats. NAO treatment significantly reduced the cytosolic cytochrome c contents and caspase-9 activity in the ischemic region but did not affect caspase-8 activity. Furthermore, NAO treatment markedly suppressed the translocation of truncated Bid, a proapoptotic Bcl-2 family member, to the mitochondrial fraction. NAO also suppressed the mitochondrial swelling and oxygen uptake stimulated by calcium overload. The results suggest that NAO possesses protective effects against myocardial I/R injury, which may be due to the suppression of cytochrome c release through blockade of truncated Bid translocation to mitochondria and inhibition of the opening of mitochondrial permeability transition pores.
 ...
PMID:Inhibition of cytochrome c release by 10-N-nonyl acridine orange, a cardiolipin-specific dye, during myocardial ischemia-reperfusion in the rat. 1994 77

Cimetidine, a histamine-2 (H2) receptor antagonist, has been demonstrated to have anticancer effects on various types of malignancies. However, the mechanisms of its action on gastric cancer are not completely understood. This study was designed to investigate its antitumor effect and underlying mechanisms in human gastric cancer SGC-7901 and MGC-803 cells. The MTT assay was used to evaluate cell viability, and flow cytometry, acridine orange staining and transmission electron microscopy were used to detect apoptosis, for cultured cells. The protein expression in cells was evaluated by Western blot analysis and colorimetric assay. Gastric tumors were established by subcutaneous injection of SGC-7901 cells in nude BALB/c mice, and cimetidine was administered to the mice. The size of tumors was monitored and the weight of tumors was examined. The exposure of gastric cancer cells to cimetidine resulted in growth inhibition and the induction of apoptosis in a dose-dependent manner. Activation of the caspase cascade for both the extrinsic and intrinsic pathways were demonstrated in vitro, including caspase-8, -9 and -3. We also found that the expression of Bcl-2 protein decreased and the expression of Bax protein increased which lead to an increase of the Bax/Bcl-2 ratio. In mice bearing SGC-7901 xenograft tumors, administration of cimetidine showed a significant decrease of tumor volumes and tumor weight compared with the control. Our results showed that cimetidine exhibited antitumor effects in gastric cancer cells with an induction of apoptosis.
 ...
PMID:Cimetidine induces apoptosis in gastric cancer cells in vitro and inhibits tumor growth in vivo. 2012 8

The role of autophagy in cisplatin anticancer action was investigated using human U251 glioma, rat C6 glioma and mouse L929 fibrosarcoma cell lines. A dose- and time-dependent induction of autophagy was observed in tumour cells following cisplatin treatment, as demonstrated by up-regulation of autophagy-inducing protein beclin-1 and subsequent appearance of acridine orange-stained acidic autophagic vesicles. The presence of autophagosomes in cisplatin-treated cells was also confirmed by electron microscopy. Inhibition of autophagy with lysosomal inhibitors bafilomycin A1 and chloroquine, or a PI3 kinase inhibitor wortmannin, markedly augmented cisplatin-triggered oxidative stress and caspase activation, leading to an increase in DNA fragmentation and apoptotic cell death. The mechanisms underlying the protective effect of autophagy apparently involved the interference with cisplatin-induced modulation of Bcl-2 family proteins, as inhibition of autophagy potentiated cisplatin-mediated up-regulation of proapoptotic Bax and down-regulation of anti-apoptotic Bcl-2. Autophagy induction in cisplatin-treated cells was preceded by activation of adenosine monophosphate-activated protein kinase (AMPK) and concomitant down-regulation of mammalian target of rapamycin (mTOR)-mediated phosphorylation of p70S6 kinase. The ability of cisplatin to trigger autophagy was reduced by small interfering RNA (siRNA)-mediated AMPK silencing, while transfection with mTOR siRNA was sufficient to trigger autophagy in tumour cells. Finally, siRNA-mediated AMPK down-regulation and AMPK inhibitor compound C increased cisplatin-induced tumour cell death, while mTOR siRNA and AMPK activator metformin protected tumour cells from cisplatin. Taken together, these data suggest that cisplatin-triggered activation of AMPK and subsequent suppression of mTOR activity can induce an autophagic response that protects tumour cells from cisplatin-mediated apoptotic death.
 ...
PMID:AMPK-mediated autophagy inhibits apoptosis in cisplatin-treated tumour cells. 2019 84

Solamargine (SM), a steroidal alkaloid glycoside from Solanum nigrum L., displayed a superior cytotoxicity to many human tumor cells. Further investigation with human K562 leukemia cells found that SM could induce an early lysosomal rupture within 2h as assessed by acridine-orange relocation and alkalinization of lysosomes. Intracellular lysosomal rupture is also confirmed with the release of cathepsin B to cytosol detected by western blot. Subsequent mitochondrial damage including mitochondrial membrane permeabilization detected by decrease membrane potential as well as the release of cytochrome c from mitochondria was also observed. The cellular Ca(2+) overload is more pronounced in SM-treated cells. Cells exposed to 10 microM SM for 30 min showed a maximum 7-fold increase in intracellular calcium concentration compared with vehicle-treated controls. The down-expression of Bcl-2, up-regulation of Bax, caspase-3 and caspase-9 activities followed by above changes revealed that the cytotoxicity of SM was involved in a lysosomal-mitochondrial death pathway induced by SM.
 ...
PMID:A lysosomal-mitochondrial death pathway is induced by solamargine in human K562 leukemia cells. 2064 40


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>